Reaction of O-methylated flavones with semicarbazide: Serendipitous selective demethylation

Özet

An unusual reaction of selective demethylation of 5-O-methylated flavones, during the reaction with semicarbazide in glacial acetic acid, is reported. The generality of the method was ascertained for various 5-O-methylated flavones. However, the method is unsuitable for chalcones, flavanones, aurones, and acetophenones. Four different flavones including heterocyclic flavone were selectively demethylated and the products were characterized by their spectral data.